全文获取类型
收费全文 | 2890篇 |
免费 | 82篇 |
国内免费 | 7篇 |
专业分类
化学 | 2213篇 |
晶体学 | 46篇 |
力学 | 21篇 |
数学 | 145篇 |
物理学 | 554篇 |
出版年
2023年 | 18篇 |
2022年 | 24篇 |
2021年 | 35篇 |
2020年 | 65篇 |
2019年 | 45篇 |
2018年 | 45篇 |
2017年 | 30篇 |
2016年 | 77篇 |
2015年 | 58篇 |
2014年 | 93篇 |
2013年 | 137篇 |
2012年 | 198篇 |
2011年 | 254篇 |
2010年 | 123篇 |
2009年 | 116篇 |
2008年 | 208篇 |
2007年 | 198篇 |
2006年 | 200篇 |
2005年 | 189篇 |
2004年 | 165篇 |
2003年 | 135篇 |
2002年 | 135篇 |
2001年 | 42篇 |
2000年 | 33篇 |
1999年 | 20篇 |
1998年 | 28篇 |
1997年 | 23篇 |
1996年 | 29篇 |
1995年 | 19篇 |
1994年 | 17篇 |
1993年 | 11篇 |
1992年 | 16篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 16篇 |
1982年 | 19篇 |
1981年 | 9篇 |
1980年 | 18篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1975年 | 8篇 |
1974年 | 4篇 |
1973年 | 4篇 |
排序方式: 共有2979条查询结果,搜索用时 15 毫秒
41.
Akter Sharmin Tanabe Tomoki Maejima Satoshi Kawauchi Satoko Sato Shunichi Hinoki Akinari Aosasa Suefumi Yamamoto Junji Nishidate Izumi 《Optical Review》2016,23(2):354-359
Optical Review - To quantify the changes in optical properties of in vivo rat liver tissue, we applied diffuse reflectance spectroscopy (DRS) system using single-reflectance fiber probe during... 相似文献
42.
The effect of oxidant species forming an alcohol molecule for hot-filament chemical vapor deposition (HFCVD) on single-walled carbon nanotubes (SWCNTs) growth has been investigated. To use a graphite rod as a filament for HFCVD to decompose alcohol sources, contamination-free sample surface can be obtained and SWCNTs are successively and densely grown at a lower temperature than those by conventional thermal CVD. It is found that the higher the molecule number of alcohol among CH3OH, C2H5OH, and 2-C3H7OH is, the lower the initial growth rate of SWCNTs is. As for CH3OH, diameter distribution of SWCNTs is dynamically changed with the growth time passed, and a negative growth rate is observed at the later stage of growth. The growth kinetics depending on the alcohol sources is discussed on the basis of a capability of the oxidant species to burn away SWCNTs and deactivation of Co catalysts used for the growth. 相似文献
43.
Yasuhiro Maeda Masaki Yumoto Norihito Saito Takayo Ogawa Kazuo Kurokawa Akihiko Nakano Masafumi Yamashita Satoshi Wada 《Optical Review》2010,17(3):305-308
We have achieved a rapid and random wavelength tuned picosecond pulsed laser and a widely tunable UV-blue picosecond pulsed
laser by using the intracavity second harmonic generation of the laser. The tuning range was from 384 to 434 nm with picosecond
pulse oscillation. In addition, we demonstrated biological imaging using a fluorescent protein excited by the widely tunable
UV-blue picosecond pulsed laser. We found that the laser is suitable for biological imaging using the fluorescent protein
as an excitation light source without damages. 相似文献
44.
Xiong Zhang Shuxia Zhang Wensheng Yang Satoshi Awaji 《Journal of magnetism and magnetic materials》2010,322(20):3023-3027
The effects of high magnetic field (10 T) on the products obtained by calcination of Co-Fe LDH precursors at different temperatures were investigated. The XRD results indicated that FeIII substituted for CoIII in Co3O4 to yield CoIICoIIIFeIIIO4 under the calcination of Co-Fe LDH precursors at 400 °C. The products obtained by magnetic field annealing at 400 °C had a porous plate-like morphology, whereas the products without magnetic field annealing were composed of nanoparticles. It was seen that CoFe2O4 phase could be formed at low temperature (about 500 °C) under the magnetic field annealing. The grain size of products obtained by magnetic field annealing at 800 °C was larger than that of zero magnetic field. It was found that the saturation magnetization was significantly enhanced after magnetic field annealing, especially at lower temperature (≤600 °C). The possible reason for the effects on the microstructure and magnetic properties of products obtained by magnetic field annealing was discussed. 相似文献
45.
Satoshi Someya Satoshi Yoshida Koji Okamoto Yan Rong Li Manabu Tange Mohammad Mezbah Uddin 《显形杂志》2010,13(1):41-47
Abstract
Droplets impinging on a hot surface that is near the Leidenfrost temperature were experimentally investigated. Ejection of jets from the top of the droplet was observed during the transient interaction between the droplet and a hot wall. We term this phenomenon jet ejection from droplets. When the bottom of the droplet initially impacts the hot surface, a jet is to be ejected from the top of the droplet. The jet ejection occurred only at low impact velocities and around the wetting limit temperature. It was not observed when droplets were dropped from large heights or when the surface was at a high temperature. 相似文献46.
The advanced color-difference formulae, CMC, CIE94, and the recently proposed CIEDE2000 formula, together with the basic CIELAB system, were estimated using the chromaticity discrimination threshold data at CIE Gray and Blue color centers. Gray is the most basic color and blue is, perceptually, in the most different region from other areas across the color space. The test stimuli, evenly distributed in the (a#x2217;, b#x2217;)-, (a#x2217;, L#x2217;)-, and (b#x2217;, L#x2217;)-plane of the CIELAB space, were generated on a CRT display, driven by a VSG system. Each direction from each color center was assessed 3 times by a panel of 9 normal color-vision observers with the psychophysical method of interleaved staircase. The experimental data were reliable and consistent with other studies according to the observer accuracy and fitted ellipse parameters. A comprehensive analysis shows the color discrimination tolerances could be well fitted by ellipses, and the CIEDE2000 and CIELAB formulae performed better than CIE94 while the CMC worst at the threshold level for the color centers studied. 相似文献
47.
48.
The effect of molecular vibrations on electronic transport is investigated with the smallest fullerene C20 bridge, utilizing the Keldysh nonequilibrium Green's function techniques combined with the tight-binding molecular-dynamics method. Large discontinuous steps appear in the differential conductance when the applied bias voltage matches particular vibrational energies. The magnitude of the step is found to vary considerably with the vibrational mode and to depend on the local electronic states besides the strength of electron-vibration coupling. On the basis of this finding, a novel way to control the molecular motion by adjusting the gate voltage is proposed. 相似文献
49.
50.
We have succeeded in precisely determining the hyperfine interactions, particularly the isomer shifts, in the 149Sm Mössbauer transition. The difference in the nuclear radii between the ground and excited states is critical for the determination of isomer shifts but is relatively small in 149Sm. Therefore, the precise determination by 149Sm Mössbauer spectroscopy is difficult. The recent development of synchrotron-radiation-based Mössbauer spectroscopy allows the isomer shifts to be determined more precisely than previously with the help of wellcollimated synchrotron radiation. In particular, the time-window effect assists the precise determination of hyperfine interactions in the 149Sm Mössbauer transition because this effect enables us to measure spectra with higher energy resolution than natural linewidth determined by the lifetime of the excited states. Meanwhile, highenergy-resolution measurements to determine center shifts by SR-based Mössbauer spectroscopy enable us to observe the second-order Doppler shift, which has not been discussed, particularly for heavy Mössbauer nuclei. We have discussed the precise determination of isomer shifts and the observation of the second-order Doppler shift using 149Sm synchrotron-radiation-based Mössbauer spectroscopy. 相似文献